Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Essays in political economy

Chapter 1. The American presidential nomination process consists of a series of elections (primaries) in which states vote at different times. The problem faced by a political party choosing the optimal temporal structure for its primaries is studied in an environment in which a sequential election may generate voter herding. By choosing the temporal structure, the party can induce voter herding which is ex ante beneficial in selecting the best candidate. When candidates have equal loyal support, simultaneous voting is optimal. When one candidate has more loyal support, a sequential election can be optimal since voter herding compensates for the loyal voter imbalance. This novel example of a beneficial information cascade contrasts results from the herding literature. Under sequential voting, states which are smaller, have fewer partisans, have more informed voters, and are more diverse optimally vote first. Chapter 2 (joint with Eleanor L. Harvill). A lack of political knowledge may be why voters policy positions often conflict with those of their favored candidate. The National Annenberg Election Survey (NAES) for the 2004 U.S. presidential election solicits citizens opinions and knowledge of candidates positions regarding specific policies, allowing us to directly estimate and analyze voters\u27 and candidates ideological positions (using Poole and Rosenthal\u27s (1985, 2000) spatial model), voters knowledge of candidates positions (using item response theory) and voting behavior. More knowledgeable individuals are far less likely to vote for the candidate farther from them. Significantly more vote mistakenly for Bush than for Kerry, so that Bush receives more votes although a significant majority of voters are ideologically closer to Kerry. Chapter 3. Two heterogeneous buyers must choose to bid on either a high or low value good which are sold in simultaneous first-price auctions. The resulting allocation is efficient only when sellers can commit to reservation prices, as the unique buyer equilibrium with fixed reservation prices exhibits coordination frictions. The high good is sold but the low value good is either not sold or sold at reservation. When sellers commit to reservation prices, a unique market equilibrium with perfect buyer coordination is achieved. The allocation and payoffs are both equivalent to the price-posting case

Coordination Frictions and Heterogeneity in Markets with Bidding

Abstract Two heterogeneous buyers with commonly known preferences must choose which one of two di¤erent goods-a high value good and a low value good-to bid on when the goods are sold through simultaneously held …rst-price auctions. We …nd that e¢ ciency of equilibrium allocation depends on allowing sellers to announce and commit to reservation prices before the auctions are held. This is achieved by …rst characterizing a unique buyer equilibrium for a generic subset of the parameter space when reservation prices are exogenously set to zero. This equilibrium exhibits coordination frictions and results in a potentially ine¢ cient allocation of the goods. The high value good is sold for sure, though it could be to either buyer and could even be at the reservation price. The low value good is either not sold or sold exactly at the reservation price to the buyer with a lower marginal valuation for the high value good. We then characterize buyer equilibria for all reservation prices. Endogenizing seller behavior by allowing sellers to announce and commit to reservation prices results in a unique market equilibrium of the game in which buyers perfectly coordinate, the e¢ cient allocation is achieved, and both allocation and payo¤s are equivalent to that of the price-posting case. The contrasting results between exogenous and endogenous reservation prices stems from the following: when the same side that searches (here, the buyer side) is responsible for price formation, coordination frictions are still present because buyers have incentive to compete over the higher value good and hence could both bid on it. However, when the passive side of the market (here, the seller side) is in e¤ect responsible (here, by setting binding reservation prices), the two-sided heterogeneity results in perfect coordination by the buyers in choosing their goods. JEL classi…cation: C78, D44

Assessment of racking deformation of rectangular underground structures by centrifuge tests

Seismic safety of buried structures has become increasingly important over the past two decades, especially after the destructive earthquakes such as in Kobe, Japan (1995), Kocaeli, Turkey (1999) and Chi-Chi, Taiwan (1999). Some of the embedded structures including pipelines, subways and tunnels collapsed or suffered severe damage in those earthquakes due to inappropriate design. The main difficulty in seismic design is the incorporation of soil-structure interaction effect governed by the relative stiffness (flexibility ratio) between the soil and the embedded structure. This study aims to clarify the effect of flexibility ratio on the dynamic response of rectangular structures buried in dry sand. For that purpose, a series of dynamic centrifuge tests were conducted on two types of box-shaped models with different rigidities under various harmonic motions. The results reveal that the magnitude of dynamic lateral earth pressure and sidewall deformation is highly dependent on the flexibility ratio of the embedded structure. Based on the flexibility ratios, racking deformations observed in centrifuge tests and racking deformations estimated through analytical approaches were evaluated in a comparative manner

Dynamic response of a flexible rectangular underground structure in sand: centrifuge modeling

Major earthquakes such as Kobe (1995), Kocaeli (1999) and Chi-Chi (Taiwan) have shown that underground structures have suffered significant damage due to dynamic loading. Therefore, recently, much priority has been given to seismic safety of underground structures located in earthquake-prone regions. There is, however, not much experimental research on the dynamic response of buried structures. This research aims to better understand the dynamic behavior of relatively flexible rectangular underground structures embedded in dry sand. To achieve this purpose, a series of dynamic centrifuge tests were conducted on a box-shaped flexible underground structure under harmonic motions with different accelerations and frequencies. Thus, response of soil and buried structure model was examined considering the dynamic soil structure interaction. Accelerometers were placed in the soil and on the buried structure model to evaluate the shear strain and acceleration response. Moreover, a special attempt was made to investigate the racking deformations by installing extensometers inside the tunnel model. Measurements obtained from those extensometers were compared with the predictions of analytical solutions. Results show that, Penzien's approach gives reasonable estimates of racking deformation for the rectangular shaped flexible underground structure

Investigation into the Effects of Textural Properties on Cuttability Performance of a Chisel Tool

The main objective of this study is to investigate the effect of textural properties of stones on cutting performance of a standard chisel tool. Therewithal, the relationships between textural properties and cutting performance parameters and physical and mechanical properties were statistically analyzed. For this purpose, physical and mechanical property tests and mineralogical and petrographic analyses were carried out on eighteen natural stone samples, which can be grouped into three fundamentally different geological origins, i.e., metamorphic, igneous, and sedimentary. Then, texture coefficient analyses were performed on the samples. To determine the cuttability of the stones; the samples were cut with a portable linear cutting machine using a standard chisel tool at different depths of cut in unrelieved (non-interactive) cutting mode. The average and maximum forces (normal and cutting) and specific energy were measured, and the obtained values were correlated with texture coefficient, packing weighting, and grain size. With reference to the relation between depth of cut and cutting performance of the chisel tool for three types of natural stone groups, specific energy decreases with increasing depth of cut, and cutting forces increase in proportion to the depth of cut. The same is observed for the relationship between packing weighting and both of specific energy and cutter forces. On the other hand, specific energy and the forces decrease while grain size increases. Based on the findings of the present study, texture coefficient has strong correlation with specific energy. Generally, the lower depth of cut values in cutting tests shows higher and more reliable correlations with texture coefficient than the increased depth of cut. The results of cutting tests show also that, at a lower depth of cut (less than 1.5 mm), even stronger correlations can be observed between texture coefficient and cutting performance. Experimental studies indicate that cutting performance of chisel tools can be predicted based on texture coefficients of the natural stones